We propose a SPORE initiative on adult glioblastoma at the Dana-Farber/Harvard Cancer Center (DF/HCC). Our objective is to improve the standard of care through the use of targeted therapies for this type of cancer. Towards this end, basic scientists from Harvard Medical School have joined with clinical/translational investigators from Brigham and Women's Hospital, Dana-Farber Cancer Institute and Massachusetts General Hospital. This initiative is supported by central cores for Pathology, Biostatistics and Administration and includes career and developmental programs. The study plan uses clinical materials and exploits a number of clinical trials to attack glioblastoma on four distinct fronts: Project one targets the tumor vascular system. A cancer biologist, Rakesh Jain, PhD and a neurooncologist, Tracy Batchelor, MD address a current impasse in vascular-based therapies for glioblastoma. Why are patient responses to bevacizumab generally transient and marginal? Jain and Batchelor will test the hypothesis that responses to VEGF pathway inhibitors can be augmented by concurrent or sequential suppression of the angiopoietin-2 signal transduction pathway. Project two targets the PI3K signaling axis - a signaling pathway that is activated in ~50% of glioblastomas. Biochemist Tom Roberts, PhD (a co-discoverer of PI3K) and neuro-oncologist Patrick Wen, MD address fundamental issues regarding PI3K signaling in glioblastoma that - when resolved - will greatly optimize the treatment of these tumors with small molecule antagonists of PI3K. Project three targets the IDH pathway. Malignant gliomas, including glioblastomas, may harbor gain-of-function mutations in isocitrate dehydrogenase 1 (IDH1) resulting in accumulation of 2-hydroxyglutarate (2- HG) promoting tumorigenesis. Molecular biologist William Kaelin, MD and neurosurgeon Daniel Cahill, MD, PhD will use clinical material to test the hypothesis that non-invasive measurement of 2-HG levels can serve as a surrogate for IDH mutant enzyme activity, and that targeting of IDH mutation and 2-HG can afford a breakthrough treatment for malignant glioma patients. Project four attacks the Olig2 transcription factor. Molecular biologist Chuck Stiles, PhD has demonstrated an oppositional relationship between the gliogenic transcription factor Olig2 and p53. Building upon these findings, Stiles and radiation oncologist Jay Loeffler, MD will use clinical materials to test the hypothesis that suppression of Olig2 will enhance radiation sensitivity of the major population of glioblastomas (~75%) that retain a structurally intact p53 gene.